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To investigate the mechanisms inducing sperm death after ejaculation, stallion ejaculates were incubated in BWW media during 6 h at 37°C. At the beginning of the incubation period and after 1, 2, 4 and 6 h sperm motility and kinematics (CASA), mitochondrial membrane potential and membrane permeability and integrity were evaluated (flow cytometry). Also, at the same time intervals, active caspase 3, hydrogen peroxide, superoxide anion (flow cytometry) and Akt phosphorylation (flow cytometry) were evaluated. Major decreases in sperm function occurred after 6 h of incubation, although after 1 h decrease in the percentages of motile and progressive motile sperm occurred. The decrease observed in sperm functionality after 6 h of incubation was accompanied by a significant increase in the production of hydrogen peroxide and the greatest increase in caspase 3 activity. Additionally, the percentage of phosphorylated Akt reached a minimum after 6 h of incubation. These results provide evidences that sperm death during in vitro incubation is largely an apoptotic phenomena, probably stimulated by endogenous production of hydrogen peroxide and the lack of prosurvival factors maintaining Akt in a phosphorylated status. Disclosing molecular mechanisms leading to sperm death may help to develop new strategies for stallion sperm conservation.  相似文献   
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IM DONGIL 《山东饲料》2013,(17):50-51
The research focuses on strategic alliances for innovation in the telecommunication industry in the Republic of Korea. The author reviews relevant literature and specifically investigates how cluster membership affects innovative performance. Later, he combines it with an endogenous factor - centrality. The main motivation is to investigate if the existing theories and theories, which are largely based in the Western context, applies in a collectivistic South Korean context.  相似文献   
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Bitches with dystocia most often present with clinical signs of uterine inertia (UI). The aetiology of myometrial dysfunction in most of these cases is still not elucidated. We compared blood ionized calcium (iCa) and glucose concentrations in bitches diagnosed with primary UI (PUI, n = 14), secondary UI (SUI, n = 6) or obstructive dystocia (OD, n = 6), and we described their haematology profiles. Bitches diagnosed with UI had a patent birth canal and delivered no puppies yet (PUI) or only part of the whole litter (SUI). The OD group had no UI and showed strong abdominal contractions. Blood iCa did not differ between the PUI, SUI and OD groups and was not influenced by litter size. There was a significant positive relationship (R2 = .241, p = .013) between iCa concentrations and the dam's body weight. Glucose concentrations were also not significantly different between dystocia groups or influenced by body weight and litter size. Hypocalcaemia was detected in 11 bitches, and hypoglycaemia in two bitches. Pregnancy‐associated anaemia was seen in about one‐third of the bitches. Eight of 12 dogs had increased platelet counts, and ten had leukocytosis with mature neutrophilia. Although iCa did not differ between dystocia groups, low concentrations may have contributed to the development of UI in some of the small size bitches. Hypoglycaemia was uncommon, and therefore, we consider low glucose concentrations not to have played an important role in the pathogenesis of UI in our study population. Pregnancy‐associated anaemia, thrombocytosis, leukocytosis and mature neutrophilia were common findings in otherwise healthy bitches diagnosed with different forms of dystocia.  相似文献   
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Mating‐induced endometritis (MIE) is ubiquitous in the horse after natural mating and artificial insemination with frozen/thawed semen causing the most aggressive response. The majority of mares eliminate MIE 24–48 h after insemination. An endometrial explant culture was tested as a potential in vitro exemplar for sperm‐induced MIE. Endometrial prostaglandin F (PGF) secretion and expression of interleukin‐8 (IL‐8) were used as markers of inflammation. Endometrial explants were cultured from uteri collected from follicular phase mares. Explants were challenged with 1 or 10 × 106 sperm/ml frozen/thawed semen, chilled semen, washed sperm or seminal plasma. Medium was collected 24 and 72 h after challenge and assayed for PGF by radioimmunoassay. Treatment of endometrial explants with frozen/thawed, chilled semen or washed sperm did not change the secretion of PGF compared with untreated controls. However, 24 h after challenge cultured explants expressed IL‐8. The in vitro endometrial explant system did not represent the in vivo response to semen when PGF was used as a marker of inflammation, yet the use of gene expression as an inflammatory marker warrants further investigation.  相似文献   
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A total of 42 ejaculates were used in the experiment; six ejaculates per stallion, obtained from seven Pure Spanish stallions (PRE), were split and frozen in freezing media with different concentrations and combinations of cryoprotectant (CPA): (i) Cáceres (skim milk based extender) containing 2.5% glycerol (2.5GL), (ii) Cáceres containing 1.5% glycerol and 1.5% dimethylformamide (1.5%GL–1.5%DMFA), (iii) Cáceres extender supplemented with 1.5% glycerol and 2.5% dimethylformamide (1.5%GL–2.5%DMFA) and (iv) Cáceres extender supplemented with 4% dimethylformamide (4%DMFA). After at least 4 weeks of storage in liquid nitrogen (LN), straws were thawed and semen analysed by computer‐assisted sperm analysis and flow cytometry (membrane lipid architecture (Merocyanine 540), integrity and sublethal damage (YoPro‐1) and mitochondrial membrane potential (JC‐1)). After thawing, better results were observed in samples frozen in 4%DMFA or in combinations of 1.5%GL–2.5%DMFA, in fact total motility increased by 16% in the 4%DMFA group compared to 2.5%GL (P < 0.05). Also, there was an increment in the percentage of progressive motile sperm in the 1.5%GL–2.5%DMFA group (9.8% 2.5GL vs 19% in the 1.5%GL–2.5%DMFA group p < 0.05); also, samples frozen in the 4%DMFA group had more intact (YoPro‐1 negative) sperm post‐thawing, 29.3% in 2.5%GL vs 36.7% in 4%DMFA group (p < 0.05). Membrane lipid architecture was not affected by any of the cryoprotectants tested, while samples frozen in 4%DFMA had a lower percentage of mitochondria with lower membrane potential. It is concluded that DMFA improves the outcome of cryopreservation of stallion spermatozoa mainly reducing sublethal cryodamage.  相似文献   
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Anti‐Müllerian hormone (AMH) is produced in the ovary, and thus, it is an excellent marker of follicle pool in females. Current interest is the clinical use of this parameter as a biomarker to assess presence or absence of an intact ovary and to diagnose ovarian remnant syndrome (ORS) following incomplete ovariohysterectomy (OHE) in bitches. The aim of this study was to evaluate serum AMH concentrations in bitches (n = 34) before and after OHE using two different commercial ELISA kits, one of which is based on detecting human AMH and the other is based on detecting human AMH and the other specified for canine AMH. Furthermore, serum AMH levels were also measured in six ORS cases to compare the diagnostic utility of the two different ELISA kits. Serum AMH concentrations measured using the human and canine kit prior to and after OHE were 0.32 ± 0.24, 0.006 ± 0.22 ng/ml (p < .001) and 12.08 ± 22.81, 9.55 ± 15.42 ng/ml (p = .868), respectively. Thus, the canine‐based kit was not able to reveal the significant drop in serum AMH levels. In conclusion, the human‐based ELISA kits successfully detected the drop in serum AMH concentrations. Reliable results can only be achieved from well‐designed ELISA kits, and AMH levels might be a useful diagnostic tool for the evaluation of presence or absence of ovaries as well as for the detection of ORS cases in bitches.  相似文献   
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